OnlineFreeToolBoxCalculators
Unit Converter
About Unit Converter
The Unit Converter converts length, weight and temperature units. Length covers millimetres, centimetres, metres, kilometres, inches, feet, yards and miles; weight covers milligrams, grams, kilograms, tonnes, ounces, pounds and stones; temperature covers Celsius, Fahrenheit and Kelvin — for example 1 Celsius is 33.8 Fahrenheit and 1 kilogram is 2.2046 pounds. Enter a value, choose the unit it is in and the unit you want, and it shows the converted value — for example 1 millimetre is 0.1 centimetres and 1 kilometre is 1000 metres. It covers the everyday conversions that come up in DIY, sewing, cooking, travel, schoolwork and online shopping.
Length is the one measurement where two systems live side by side: metric in most of the world and imperial in the United States and in some trades. A single wrong conversion can ruin a cut, a fit or a delivery, so having the conversion done exactly matters more than it looks.
How to use Unit Converter
- Pick a category: Length, Weight or Temperature.
- Enter the value in the “Value” field.
- Choose the starting unit in the “From” list.
- Choose the target unit in the “To” list (or press the swap button to reverse them).
- Press “Convert” and read the result — it also updates live as you type.
Why use Unit Converter
It removes the most common conversion mistakes: misplaced decimal points, mixing up inches and centimetres, and guessing at miles and kilometres.
- Both systems — metric and imperial length units in one place.
- Exact results — conversions are calculated, not rounded to a rough guess.
- Practical — useful for DIY, fabric, furniture, travel distances and homework.
Common uses
Common uses include converting recipe measurements in the kitchen, switching between miles and kilometres when travelling, converting feet and inches for DIY projects, and changing weights between kilograms and pounds for fitness or postage. Students use it for homework, and cooks for scaling recipes up or down.
Your privacy
The value and units you enter are processed in your browser only and are never uploaded or stored.
Frequently asked questions
Which units are supported?
Length units: millimetres, centimetres, metres, kilometres, inches, feet and miles.
How many centimetres are in an inch?
Exactly 2.54 centimetres. That exact definition is what the converter uses.
Can I convert miles to kilometres?
Yes. Choose miles as the “From” unit and kilometres as the “To” unit — 1 mile is about 1.609 kilometres.
Does it convert weight or temperature?
No. This page converts length units only. Weight, volume and temperature need their own converters.
Why does my result have many decimal places?
Conversions are shown with decimal places so small values stay accurate. Round the result to the precision your job needs.